US2559049A - Constant tension flight control device for model airplanes - Google Patents

Description

o. L. ST. CLAIR 2,559,049

CONSTANT TENSION FLIGHT CONTROL DEVICE FOR MODEL AIRPLANES July 3, 1951 3 Sheets-Sheet 1 Filed June 29, 1948 O.L.SZ .UZa/ir July 3, 1951' o. L. ST. CLAIR 2,559,049

CONSTANT TENSION FLIGHT CONTROL DEVIGE FOR MODEL AIRPLANES Filed June 29, 1948 3 Sheets-Sheet 2 ununulllllllln swam/M 2, [i I CzLa iflza/ir CONSTANT TENSION FLIGHT CONTROL DEVICE FOR MODEL AIRPLANES Filed June 29, 1948 O- L. ST. CLAIR July 3, 1951 3 Sheets-Sheet 5 a ZLHZL'Zazr Patented July 3, 1951 OFFICE CONSTANT TENSION FLIGHT CONTROL DEVICE FOR MODEL AIRPLANES Oba L. St. Clair, Eugene, Oreg.

Application June 29, 1948, Serial No. 35,801

7 Claims. 1

This invention relates to a'fiight control mechanism for gasoline powered model airplanes.

It is an object of this invention to provide a flight control mechanism for connection between a model airplane in flight and a central control on the ground whereby the'airplane in flight may be fully controlled by an operator on the ground.

In the use of flight controls extending from the model in flight to a control mechanism on the ground, it is necessary that flexible means be utilized to provide for the free motion of the plane. Heretofore, in the use of such a control device, when the model moves towards the operator, the tension of the flexible connecting members is relaxed and the full control thereof is lost. With the use of the mechanism of this invention, means is provided for maintaining a constant tension on the control cables between the plane and operator irrespective of the relative position of the plane to the operator or the direction of the flight.

Another object of this invention is to provide a flight control mechanism of this kind which includes operative control connecting means between the operator and the control surfaces of the model, and operative control means for the engine.

Still another object of this invention is to provide a flight control for model airplanes whereby an operator on the ground may have full control of the control surfaces of the plane and the engine throttle.

A further object of this invention is to provide a flight control mechanism of the kind to be more particularly described hereinafter wherein the operators controls substantially simulate the control structure normally found in ,full scale planes and operates in substantially the same manner,

Yet another object of this invention is to provide a control mechanism for actuating the control surfaces of a model airplane in flight wherein the actuation of one of the control surfaces effects the operation of the engine.

The full effect of the control mechanism to be herein described is maintained by the mechanism of the entire device which maintains a constant tension on the flexible cables between the operator and the plane, without which the operator would not maintain full control in all attitudes and positions of the plane relative to the operator.

To the foregoing objects, and others which may hereinafter more fully appear, the invention consists of the novel construction, combination and arrangement of parts, as will be more specifically referred to and illustrated in the accompanying drawings, but it is to be understood that changes, variations, and modifications may be resorted to which fall within the scope of the invention as claimed.

In the drawings:

Figure 1 is a perspective diagrammatic view of the airplane control constructed according to an embodiment of this invention.

Figure 1a is a perspective view of the operators control unit.

Figure 2 is a top plan view, partly broken away and partly in section, of the operators control unit.

Figure 3 is a side elevation, partly broken away and partly in section.

Figure 4 is a fragmentary detailed section taken on the line 4-4 of Figure 3.

Figure 5 is a top plan view, partly broken away and partly in section of the airplane control unit.

Figure 6 is a longitudinal section of the airplane control unit.

Figure 7 is a transverse section.

Figure 8 is a fragmentary detailed section taken on the line 8-8 of Figure 2.

Referring to the drawings, the numeral l0 designates generally an airplane control unit for a gasoline powered model airplane and the numeral ll designates generally an operators control unit for association with the airplane control unit Ill. The unit [0 is adapted to be fixed to and mounted in th model airplane for manipulating the flight controls and the throttle of the engine and is connected by suitable cables or other flexible members to the operators control unit I I. The control unit I l is adapted to be mounted on the ground in the center of the flight area and is mounted for rotation to be rotated about a fixed base by the operation of the model. The operator by sitting at the flight control unit II is able to control the direction of flight and the climb and dive attitude of the model together with the throttle during all phases of the flight.

Airplane control unit The bight portion I5 of the frame I2,

bight member towards engagement with the fixed plate I5.

A pivot pin as engages through the free end of the frame member I2 at the opposite ends A pair of pulleys as 2| and 2 2 are 4 by a suitable pivot pin 46. The pin 46 is spaced outwardly from the pin 2'1 on which the segment is mounted. The rear end of the control rod 45 is pivotally mounted to the lower end of the depending horn 45 of the elevators.

In this manner the pulleys 2I and 22 are operatively connected to the aileron and elevator controls of the airplane while the frame I2 on which the pulleys are mounted is operatively connected to the rudder movement. The aileron controls are also connected to the throttle mechanism of the engine in the model. A forwardly extending rod as at is pivotally connected to the upper side of the lower segment gear 29. A plate 28; is fixedly mounted in the model plane forwardly of the frame I2. A lever as 45 is pivotally connected by a pivot pin 55 onto the mountrotatably mounted within the frame I2 between' theupper and lower plates thereof. The pulleys 2| and 22 are both provided with double grooves aboutwhich cables to be described hereinafter may be. engaged.

The upper pulley 2! is provided with a depending pinion 24 and the lower pulley 22 isprovided with an upstanding pinion 25'. The pinions 24 and 25 are fixed to or otherwise mounted for simultaneous rotation with the respective pulleys. Both of the pinions 24 and 25 confront each other on the pivot bolt or pin 26. The pivot pin 26 extends through the plates I4 at the free end of theycrossarm of the T frame. A second pivot pin as 21 is fixed between the plates I4 of the frame between the pin 26 and the bight member I5. A pair of segment gearsas 28 and 29' are rockably mounted on the pin 21 intermediate the length'thereof within the frame I2. The teeth of the gears 28 engage the gears of the pinion ing plate at. The forward end of the control rod E? is formed with an elongated slot 53. A pin 5| fixed on the lower end of the lever 49 loosely engages in the slot 53 to provide a lost motion connection between the rod 57 and the lever 45.

Asegment of a ratchet gear 52 is fixed to or formed on the lever 49 concentric to the pivot 55 thereof. A pawl 56 is pivotally mounted by the pin 55 onto the plate 53 adjacent the ratchet 52. A tooth 55 of the pawl 56. engages the teeth of the ratchet 52 to provide for the movement of the ratchet and lever in one direction. A spring as 5? is fixed to one arm of the lever 56 on which the pawl is mounted and constantly urges the tooth 56 into engagement with the teeth of the ratchet. A pin as 58'is fixed to the'depending arm 2 4. so that the segment 28 will be rocked about the' pivotpin 21 upon rotation of the pulley 2|. The teeth of the segment gear 29 engage the lower pinion 25 so that the lower segment 29 may be rocked upon rotation of the lower pulley 22 about the pivot pin 26. A rearwardly extending lever arm. is fixed to or formed on one side of the lower segment 29. The lever arm 33 extends substantially directly rearwardly of the pivot pin 21. The lever arm 3|] is provided for attachment to the control members which are connected to the ailerons of the model. The upper segment 28 is attached by rods and levers to the elevator of the model and the rudder is connected directly to the frame I2.

A lever arm 3i is fixed to or formed onthe frame I2 at the rear end thereof and extends outwardly from the pivot pin 20 which rockably mounts the frame I 2 within the plane. A link as 32 is rockably connected to the outer end of the lever arm 3| and is connected at its rear end to the horn 34 of the rudder. The outwardly extending rods 35 and 35 as shown in Figure 5 are connected between the lever arm 30 of the segment 29 and the aileron bell cranks. The rod or link 35 is pivotally connected to the free end of the lever arm 35 by a pin 31 and the outer end of the rod 35 is connected to one arm of the right aileron bell crank 38. The other arm of the bell crank 38 is connected by a link 39 to the horn 40 of the right aileron. The link or rod 36 extends outwardly to the other side of the model and is connected at its outer end to the bell crank 41 which in turn is connected by a rod 42 to the horn 44 of the left aileron.

A rearwardly extending rod .or link 45 is pivotallyconnected to the upper segment gear 28 of the lever 54 and a lug as 59 fixed adjacent the forward end of the rod ll engages the pin 58 upon movement of the rods? rearwardly for disengaging the pawl from the ratchet.

rod as 55 extends forwardly from the lever 65 for connection to the throttle control of the gasoline powered engine. The rear end of the rod 50 is pivotally connected by a pin 5| to the lever 39 above the pivot thereof and a spring as 6,2 connected also to the upper end of the lever 69, constantly urges the upper arm of the lever and the rod 55 forwardly to the throttle off position.

"Flexible cables or wires as 65 and 55 connect the airplane control unit Iii'to the operators control unit II. One set of cables as 64 engages about the lower pulley 22 and another set of cables as 55. engages about the upper pulley 2|. lothof the cables 54 and 55 engage through a fairl'ead 66 fixed to or otherwise mounted on the model. The fairlead 55 or guide member may be mounted on the wing tip or in the forward portion of the fuselage.

In the use and operation of the airplane flight control Iflthe rudder of the model is initially set. for steering the model outwardly from the circle within which it is tethered. The airplane in..fiight will then be biased toward turning to the right or away from-the center of its flight circle. This biased direction of flight will cause the'plane to exert a tension on'all of the cables fi lland. 65. This tension will in turn pull the framej2 .counterclockwise when looking down on Figure l of the-drawings. The movement to the left ofthe frame I2 about its pivot 20 will cause the rudder to turn to the left thereby releasing some of-the strain off the cables and maintainin the direction of the airplanes flight substantially inthearc of the circle. The vertical direction ofthe-modelmay be controlled by varying the tension on the cable 65 which engages about the upper pulley 2!. The cable 65 is looped about the pulley 2| so that one stretch of the cable engages in the upper groove and the lower stretch engages in the lower groove. The lower stretch of the cable 65 tangentially engages the forward side of the pulley so that as the forward stretch of the cable is tensioned the pulley 2| will be rotated or at least biased for rotation in a counterclockwise direction. This rotation of the pulley 2| will move the rod 45 forwardly thus pulling the elevator down and directing the flight of the model downwardly. Tensioning of the rear stretch of the cable 65 will effect rotation of the pulley 2| in a clockwise direction for raising the elevator and thus pulling the nose of the plane upwardly.

The lower stretch of the cable 64 engages the forward side of the lower groove of the pulley 22. The upper stretch of the cable 64 extends tangentially from the rear edge of the upper groove of the pulley 22 for controlling the ailerons and the engine. Tensioning of the forward stretch of the cable 64 will effect rotation of the lower pulley 22 in a counter-clockwise direction for lowering the left wing of the plane. As the pulley 22 is rotated or biased or rotation in the counterclockwise direction, the lever arm 39 carried by the segment 29 is moved to the left as viewed in Figures 1 and 5 of the drawings. Movement of the rod 36 to the left will then effect rocking of the aileron control lever 4| in a clockwise direction thus raising the left aileron and causing the model to bank to the left. The rear stretch of the cable 64 engaging the opposite side of the pulley 22 when tensioned will effect the reverse movement of the segment 29 and rod 35 thus causing the model to bank to the right.

The control system is so arranged that movement of the controls for putting the plane in a left bank will effect the rocking of the lever 49 which controls the throttle of the engine. As the pulley 22 is moved in the counter-clockwise direction, the rear end of the slot 53 will engage the pin 5! on the lever 49. Subsequent small .movements of the rod 41 forwardly will thus effect the rotation or pivoted movement of the lever 49 in a clockwise direction about its pivot 50 thereby moving the teeth of the ratchet 52 downwardly. The pawl 54 will engage in the teeth of the ratchet for holding the lever 49 in its position during the intermittent movement thereof. This step by step movement of the lever 49 in the clockwise direction will move the rod 69 rearwardly relative to the engin thus opening the throttle. For closing the engine or moving the throttle to the off position the pulley 22 is rotated in a clockwise direction so that the rod 41 is moved rearwardly. Rearward movement of the rod 41 will cause the pin 5! to be moved forwardly in the groove 53. At the extreme movement of the rod 41 rearwardly the lug 59 will engage the pin 58 on the lever 54 thus rocking the lever 54 counter-clockwise about its pivot 55 thereby releasing the tooth 56 of the pawl from the ratchet 52 and the spring 62 will bias the lever 49 and the arm 60 forwardly to the throttle off position.

operators control unit The flexible cables 64 and 65 which extend outwardly from the fairlead 66 on the model are connected at their extreme inner end to the operators control unit H. The operators control unit II is formed of a fixed base 18 having an upstanding bearing member H at the center thereof. A pedestal as 12 extends upwardly from the base l0 and is rotatably mounted on the bearing member 1 l. The pedestal 12 is free for rotation about the bearing H durin the flight of the model. An operators seat as 14 is fixed on a rearwardly extending arm 15 which in turn is fixed at its forward end onto the pedestal 12. Simulated rudder pedals as 16 are fixed to the pedestal 12 by a forwardly extending supporting arm 11. The rudder pedals 16 are fixed and in no way control the flight of the airplane but are so related to the seat 14 that the position of the operator relative to the base 16 and pedestal 12 is similar to the position of a pilot in the cockpit of a plane.

. A horizontal supporting member as 18 is pivotally mounted to the upper end of the pedestal 12. The supporting member 18 is formed of a hollow tube open at both ends thereof. A depending ear as 19 is fixed to the lower surface of the supporting member 18 intermediate its length and engages between a pair of ears fixed to or formed on the upper end of the pedestal 12. A pivot pin 8| extends through the ears (9 and 80 for pivotally mounting the supporting member 18 at the upper end of the pedestal 12. At the forward end of the tubular supporting member 18 there are provided a pair of opposed T-shaped guide members 82 and 83. The T-shaped guide member 82 is formed with an upwardly extending arm 84 having a cross arm 85 at the upper end thereof. The lower end of the upwardly extending arm 84 is rotatably supported in a bearing block 86 fixed to the forward end of the supporting member 18. Pulleys are rotatably supported on the opposite ends of the cross arm 85 of the guide member 82 about which both links of the upper control cable 65 may be engaged- The control cable 65 as it leaves the model is guided into two stretches and each stretch is trained over one of the pulleys at one end of the cross arm 85. The cable is then directed radially of the supporting member 18 and engages through an opening 81 in the bearing block 86. The stretches of the cable 65 are then engaged over the pulleys 88 so that the cable may be extended along the length of the supporting member 18 interiorly thereof.

The lower guide member 83 is formed with a dependin arm 89 having a cross arm 90 fixed at the lower end thereof. The upper end of the supporting arm 89 is rotatably mounted in the bearing block 86 directly opposite from the supporting arm 84 of the guide member 82. The stretches of the cable 64 are trained about pulleys rotatably supported on the opposite ends of the cross arm 99. The cable stretches 64 are then directed radially of the supporting member 78 and engage about the lower pulleys at the inner end of other openings 92 directly opposite from the openings 8'! described above. Both stretches of the lower cable 64 will then be directed rearwardly in the supporting member 18 parallel to the cable 65 also directed along the length of the supportin member. A forwardly extending rod as 94 is fixed to the center of the bearing block 86 and is directed forwardly from the guide member 18 in the direction of the model. An H- shaped guide member 95 is fixed to the forward end of the supporting arm 94.

Pulleys as 96 are rotatably supported on the opposite ends of the horizontal parallel arms thereof so that the flexible cables 64 and 65 may be straightened in their direction before they come into engagement with the pulleys 91 mounted on the opposite ends of the cross arms of the guide members 82 and 83 described above. The ends of the cables 64 and 65 are wound about a 7 winding drum 98 rotatably supported on me other end of the tubular supporting member 18.

The winding drum 9.3 is mounted withinv a housing 99: havin a tubularsupporting member I09 on one side thereof. Asleeve IUI open at both ends is fixed to the free end of the tubular member I8. The sleeve Iel is fixed on the supporting member I8 and the tubular portion of the housing 99 slidably engages within the connecting sleeve IilI. A spring I62 is disposed within the connecting sleeve IQI and bears against the free inner end of the tubular member IIJO. The flexible cables extend through the tubular portion Hill of the housing 59 and then engage into grooves of the ii-grooved winding drum 98.

A brake member IE4 is mounted within the housing 99. The brake comprises a brake drum IE5 rotatably supported in the housing and a brake band I66 operatively disposed about the periphery of the drum. A shaft I! is journalled at one end in one wall of the housing 99 as shown in Figure 2 of the drawings and the other end of the shaft H3! is journalled in the brake drum I135. The pulley 98 is fixed on the shaft ID'I for rotation therewith. A ratchet HIS is fixed on the shaft I67 for rotation with the Winding drum. 98. The ratchet may be keyed onto the'shaft by a key I09 as shown in Figure 8 of the drawings. A

pawl H6 is rockably mounted on the inner surrotate in one direction relative to the brake drum Hi and the rotation of the brake drum is re-' strained by the engagement of the brake band thereabout.

A cam member i I4 engages the brake band I68 at one terminal end thereof for controlling the tension of the brake band about the brake drum I05. The cam H4 i mounted at one end of a control shaft H5 journalled in the wall's'of the housing 99. A control lever He is fixedv on the end of the shaft IE5 outwardly of the housing 99. A Bowden cable is connected to the lever I I 5 for controlling the brake. The Bowden cable includes an outer flexible tubular housing III which is fixed at one end to the housing 99 and Ill at the other end to the supporting member I8.

The inner flexible member IIil of the Bowden cable is slidable in the housing II! and is connected at one end to the control lever IIB. A brake control lever H9 is rockably mounted on the supportin member I8 by a pivot I20. handle as I2! is fixed or formed on the free arm of the lever I I9 to provide a grip for the operator in controlling the brake.

A coiled spring as I22 is mounted within the housing 99 for constantly biasing the winding drum 98 in one direction. A gear I24 is operatively connected to the spring I22 and engages in a pinion gear I25 fixedly mounted on the shaft I Ill on which the winding drum 98 is mounted- The p ng I22 constantly biases the E1? 8 will pull the cables 64 and 65 inwardly at all times and the cables may be drawn outwardly only by releasing the brake band about the brake drum IE5.

A control stick I26 is mounted on the supporting. member I8 for controlling the tension of selected ones of the stretches of the flexible cables 64 and 65. The control stick I26 is pivotally mounted intermediate its length on a shaft I21 for movement in a plane parallel to the longitudinal axis of the supporting member I8. The shaft I2I is rotatable supported in a pair of bearings I28 fixed on one side of the supporting member 18. A pivot pin I29 extends through one end of the shaft I2I for mounting the control stick I26 thereon. A radially extending arm I30 extends from the upwardly extending rotatable arm 84 of the guide member 82. The arm I30 is rigidly connected to the member 84 and pivotally connected to link I3I, link I3I being rigidly connected to shaft I21. A link as I3I is connected between the arm I21 and the arm :30 for rotating the bearing member 82 about its vertical axis. The link I3I rotates with the shaft I21 and is free to pivot in a plane passing through the axis of rotation of the shaft IZ'I. By moving the control stick I26 forwardly or rearwardly relative to the seat I4 the shaft I2? is caused to rotate in the bearings I28. Rotation of the shaft I2! will effect rocking movement of the link I3I about the axis of the shaft I2'I. This movement will in turn effect rotation of the Vertical arm 84 about a vertical axis thereby moving the ends of the horizontal arm toward or away from the model and also increasing the tension on one stretch of the cable 65 and decreasing the tension on the other stretch of the cable. This variation in tension on the stretches of the cables 55 will effeet the rotation of the correlated pulley 2I in the airplane control unit. In other words, move-' ment of the control stick I26 foreand aft relative to the seat 14 will effect the movement of the elevator in the same relative relation as the movement of the control stick of an airplane. Pivoted' movement of the control stick I25 to either side of the pivot i29 effects the control of the ailerons of the'model.

An arm I32 is fixed on the vertical arm '89 of the guide member 83. The arm I32 extends parallel to the horizontal arm 98 of the guide member 83. A link or rod I34 is fixedly connected to the freeend of arm I32 at one end and at the other end'universally pivotally connected to the end of the control stick I23. The movement of the control stick about the pivot I29 in a plane along the length of the axis of the supporting member 18 will eflect rotation of the guide member 83 about the axis of its supporting arm 89. This ro-' tation of the guide member .83 will control selectively the'tension of one of the stretches of the cable 64 engaging this guide member. This side movement of the control stick I26 will then control the rotation of the pulley 22 of the airplane control unit thus effecting the movement of the ailerons of the model and, in turn, the throttle opening of the engine.

In this manner thercomple te control of the model airplane is effected'by the operator at all times by using the con-trolunit' I I thus described.

- The airplane is fully tetheredto the control unit I I and as the model traverses the circular flight path, the-control unit I I is rotated about the supporting base and the operator sitting on the seat I4 which is fixed on'the pedestal "I2will at all times be in the same relative position to the airplane throughout the entire flight.

Having thus described my invention, what I claim is:

1. An airplane control unit for an airplane having movable control surfaces and an engine, adapted for connection to an operators control unit, comprising a frame, means pivotally mounting said frame on said airplane, resilient means biasing said frame towards one position in said airplane, control members rockably mounted on said frame, means connecting said frame to one of said control surfaces for actuation upon movement of said frame on its pivot, means operatively connected between said control members and the other control surfaces for actuation upon rocking of said members, engine control means operably connected between said engine and one of said control members for actuating said engine control upon actuation of one of said other control surfaces, and flexible members connected between said control members and said operators control unit. a

2. An airplane control unit for an airplane having a movable rudder, ailerons and elevator, and adapted for connection to a remote operators control unit, comprising a frame, means pivotally mounting said frame on said airplane, spring means biasing said frame to one pivoted position, a lever arm fixed on said frame, a rod pivotally connected at its ends between said arm and the rudder for moving the rudder upon pivoted movement of said frame, a pair of control members rockably mounted on said frame, a control lever pivotally mounted on said frame adjacent one of said members, a lever arm on said control lever, links connected between said latter lever arm and said ailerons, a gear segment fixed on said lever, a pinion on each of said control members, a second gear segment rockably mounted on said frame, said pinions engaging said segments efiecting the movement thereof upon rocking of said members, a link between said second segment and the elevator, and a flexible connecting member between said control members and said operators control unit.

3. An airplane control unit for a powered airplane having a rudder, ailerons, elevator, and an engine control rod, and adapted for connection to a remote operators control unit, comprising a frame, means pivotally mounting said frame on said plane, resilient means biasing said frame to one pivoted position, a rod connected between said frame and said rudder for moving the rudder upon movement of said frame about its pivot, a pair of control members rockably mounted on said frame, a pinion fixed on each of said members, a pair of gear segments rockably mounted on said frame, each of said segments engaging one of said pinions, a connecting rod between one of said segments and said elevator, a con-. necting rod between said ailerons and the other segment, a flexible connecting member between said control members and said operators control, and a rod pivotally mounted on said other segment operatively connected to said engine control rod.

4. An airplane control unit for a powered airplane having a rudder, ailerons, elevator, and an engine control rod, and adapted for connection to a remote operators control unit, comprising a frame, means pivotally mounting said frame on said plane, resilient means biasing said frame to one pivoted position, a rod connected between said frame and said rudder for moving the rudder upon movement of said frame about its pivot, a pair of control members rockably mounted on .10 said frame, a pinion fixed on each of said members, a pair of gear segments rockably'mounted on said frame, each of said segments engaging one of said pinions, a connecting rod between one of said segments and said elevator, a connecting rod between said ailerons and the other segment, a flexible connecting member between said control members and said operators control, a rod pivoted at one end on said other segment, a lever pivoted intermediate the length thereof forwardly of said frame, a lost motion connection between said latter rod and said latter lever, ratchet teeth on said latter lever radially of the pivot thereof, a spring pressed pawl engaging said ratchet teeth for limiting the movement of said lever to one direction upon movement of said latter rod in one direction and a lug on said latter-rod enga'geable with said pawl upon movement of the rod in the opposite direction for disengaging said pawl from said ratchet.

5. In a flight control device for engine powered model airplanes having movable control surfaces and an engine throttle, an airplane control unit for connection to an operators control unit, comprising a frame pivoted in said plane, means connecting said frame to one of said control surfaces for movement thereby, a pair of control members rockably mounted on said frame, means connecting said control members to the other control surfaces, an engine throttle control member pivotally connected to one of said control members, means operative on movement of said throttle control member in one direction for moving the throttle in one direction, said latter means including means operative upon movement of said latter member in the opposite direction for mov ing the throttle in the opposite direction.

6. In a constant tension flight control device for powered model airplanes having an airplane control unit, an operators control unit and flexible connecting members between said control units, said operators control unit comprising a base, a pedestal rotatably mounted on said base, a horizontal tubular member pivotally mounted on said pedestal, a shaft disposed parallel to said tubular member and rotatably carried by the latter, a control lever, a pivot mounting said lever on said shaft, a winding drum on one end of said tubular member, said flexible members extending through said tubular member and being engaged about said drum, spring means constantly biasing said drum for rotation in one direction, means controllably limiting the rotation of the drum in the opposite direction, a pair of opposed guide members rotatably mounted on the other end of said tubular member, said flexible members being trained over the opposite ends of said guide members, means operably connecting one of said guide members with said control lever for rotation thereby, means operably connecting the other of said guide members with said rotatable shaft for rotation thereby, whereby said control lever and shaft may be actuated for selectively varying the tension on selected flexible members thereby effecting operation of said airplane control unit.

'7. In a constant tension flight control device for powered model airplanes having an airplane control unit, an operators control unit and flexible connecting members between said control units, said operators control unit comprising a base, a pedestal rotatably mounted on said base, a horizontal tubular member rockably mounted on said pedestal, a brake drum rotatably mounted on one end of said tubular member, a winding "drum rotatably mounted on said one end concentrically with said brake drum, means carriedby said drums limiting the rotation of said winding cross arms thereof into said tubular member and a about said winding drum, a control stick swivellably mounted on said tubular member, and means connecting each of said guide members to said control stick for separate rotation upon movement of said stick in separate vertical planes for selectively controlling the tension on selected ones of said flexible-members.

' OBA L. ST. CLAIR.

'12 REFERENCES OiTED The following references are of record in th 'file of this patent: V

UNITED STATES, PATENTS Number Name Date Helmke Dec. 29, 1931 Sampson Nov. 24, 1936 Walker Aug. 11, 1942 Kelecius Dec. 4, 1945 Padgett July 30, 1946 Walker Sept. 3, 1946 Nash et a1 Dec. 9, 1947 Effinger Sept. 26,1950

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